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          <th colspan="3" align="center">DB-&gt;del()</th>
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          <td width="20%" align="left"><a accesskey="p" href="dbcreate.html">Prev</a> </td>
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                The DB Handle
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    <div class="sect1" lang="en" xml:lang="en">
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            <h2 class="title" style="clear: both"><a id="dbdel"></a>DB-&gt;del()</h2>
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      <pre class="programlisting">#include &lt;db.h&gt;

int
DB-&gt;del(DB *db, DB_TXN *txnid, DBT *key, u_int32_t flags);  </pre>
      <p>
         The <code class="methodname">DB-&gt;del()</code> method removes key/data pairs from the database.  The
         key/data pair associated with the specified <span class="bold"><strong>key</strong></span> is discarded from the database.  In the
         presence of duplicate key values, all records associated with the
         designated key will be discarded.
    </p>
      <p>
         When called on a database that has been made into a secondary index
         using the <a class="xref" href="dbassociate.html" title="DB-&gt;associate()">DB-&gt;associate()</a>  method, the
         <code class="methodname">DB-&gt;del()</code> method deletes the key/data pair from the primary database
         and all secondary indices.
    </p>
      <p>
         The <code class="methodname">DB-&gt;del()</code> method will return <a href="../../programmer_reference/program_errorret.html#program_errorret.DB_NOTFOUND" class="olink">DB_NOTFOUND</a> if the specified key
         is not in the database. The <code class="methodname">DB-&gt;del()</code> method will return <a href="../../programmer_reference/program_errorret.html#program_errorret.DB_KEYEMPTY" class="olink">DB_KEYEMPTY</a> if the database is a
         Queue or Recno database and the specified key exists, but was never explicitly created by
         the application or was later deleted. Unless otherwise specified, the
         <code class="methodname">DB-&gt;del()</code> <span>
            <span>
                  method returns a non-zero error value on failure and 0 on success.
            </span>
            
        </span>
    </p>
      <div class="sect2" lang="en" xml:lang="en">
        <div class="titlepage">
          <div>
            <div>
              <h3 class="title"><a id="idp49460064"></a>Parameters</h3>
            </div>
          </div>
        </div>
        <div class="sect3" lang="en" xml:lang="en">
          <div class="titlepage">
            <div>
              <div>
                <h4 class="title"><a id="idp49460568"></a>txnid</h4>
              </div>
            </div>
          </div>
          <p>
                If the operation is part of an application-specified transaction, the
                <span class="bold"><strong>txnid</strong></span> parameter is a transaction
                handle returned from <a class="xref" href="txnbegin.html" title="DB_ENV-&gt;txn_begin()">DB_ENV-&gt;txn_begin()</a>; 
                if the operation is part of a Berkeley DB Concurrent Data Store group, the
                <span class="bold"><strong>txnid</strong></span> parameter is a handle returned
                from <a class="xref" href="envcdsgroup_begin.html" title="DB_ENV-&gt;cdsgroup_begin()">DB_ENV-&gt;cdsgroup_begin()</a>;
                otherwise NULL. If no transaction handle is specified, but the
                operation occurs in a transactional database, the operation will be
                implicitly transaction protected.
            </p>
        </div>
        <div class="sect3" lang="en" xml:lang="en">
          <div class="titlepage">
            <div>
              <div>
                <h4 class="title"><a id="idp49439848"></a>key</h4>
              </div>
            </div>
          </div>
          <p>
                The key <a class="link" href="dbt.html" title="Chapter 4.  The DBT Handle">DBT</a>  operated on.
            </p>
        </div>
        <div class="sect3" lang="en" xml:lang="en">
          <div class="titlepage">
            <div>
              <div>
                <h4 class="title"><a id="idp49299600"></a>flags</h4>
              </div>
            </div>
          </div>
          <p>
                          The <span class="bold"><strong>flags</strong></span> parameter must be set to 0
                          or one of the following values:
                     </p>
          <div class="itemizedlist">
            <ul type="disc">
              <li>
                <p><a id="dbput_DB_CONSUME"></a>
                  <code class="literal">DB_CONSUME</code>
            </p>
                <p>
	     	If the database is of type DB_QUEUE then this flag may be set to force the head of the queue
		to move to the first non-deleted item in the queue.  Normally this is only done if the
		deleted item is exactly at the head when deleted.
            </p>
              </li>
              <li>
                <p><a id="del_DB_MULTIPLE"></a>
                  <code class="literal">DB_MULTIPLE</code>
            </p>
                <p>
                Delete multiple data items using keys from the buffer to which the 
                <span class="bold"><strong>key</strong></span> parameter refers.
            </p>
                <p>
                To delete records in bulk by key with the btree or hash access methods, construct a
                bulk buffer in the <span class="bold"><strong>key</strong></span> 
                <a class="link" href="dbt.html" title="Chapter 4.  The DBT Handle">DBT</a> using 
                <a class="xref" href="DB_MULTIPLE_WRITE_INIT.html" title="DB_MULTIPLE_WRITE_INIT">DB_MULTIPLE_WRITE_INIT</a> and 
                <a class="xref" href="DB_MULTIPLE_WRITE_NEXT.html" title="DB_MULTIPLE_WRITE_NEXT">DB_MULTIPLE_WRITE_NEXT</a>.  To
                delete records in bulk by record number, construct the 
                <span class="bold"><strong>key</strong></span> <a class="link" href="dbt.html" title="Chapter 4.  The DBT Handle">DBT</a> using 
                <a class="xref" href="DB_MULTIPLE_RECNO_WRITE_INIT.html" title="DB_MULTIPLE_RECNO_WRITE_INIT">DB_MULTIPLE_RECNO_WRITE_INIT</a> and 
                <a class="xref" href="DB_MULTIPLE_RECNO_WRITE_NEXT.html" title="DB_MULTIPLE_RECNO_WRITE_NEXT">DB_MULTIPLE_RECNO_WRITE_NEXT</a> 
                with a data size of zero.
            </p>
                <p>
                A successful bulk delete operation is logically equivalent to a loop through each
                key/data pair, performing a <a class="xref" href="dbdel.html" title="DB-&gt;del()">DB-&gt;del()</a> for each one.
            </p>
                <p>
                See the <a class="xref" href="dbt.html#dbtlist" title="DBT and Bulk Operations">DBT and Bulk Operations</a> for more information on
                working with bulk updates.
            </p>
                <p>
                The <code class="literal">DB_MULTIPLE</code> flag may only be used alone.
            </p>
              </li>
              <li>
                <p><a id="del_DB_MULTIPLE_KEY"></a>
                  <code class="literal">DB_MULTIPLE_KEY</code>
            </p>
                <p>
                Delete multiple data items using keys and data from the buffer to which the 
                <span class="bold"><strong>key</strong></span> parameter refers.
            </p>
                <p>
                To delete records in bulk with the btree or hash access methods, construct a bulk
                buffer in the <span class="bold"><strong>key</strong></span> 
                <a class="link" href="dbt.html" title="Chapter 4.  The DBT Handle">DBT</a> using 
                <a class="xref" href="DB_MULTIPLE_WRITE_INIT.html" title="DB_MULTIPLE_WRITE_INIT">DB_MULTIPLE_WRITE_INIT</a> and 
                <a class="xref" href="DB_MULTIPLE_KEY_WRITE_NEXT.html" title="DB_MULTIPLE_KEY_WRITE_NEXT">DB_MULTIPLE_KEY_WRITE_NEXT</a>.  
                To delete records in bulk with the recno or hash access methods, construct
                a bulk buffer in the <span class="bold"><strong>key</strong></span> 
                <a class="link" href="dbt.html" title="Chapter 4.  The DBT Handle">DBT</a> using 
                <a class="xref" href="DB_MULTIPLE_RECNO_WRITE_INIT.html" title="DB_MULTIPLE_RECNO_WRITE_INIT">DB_MULTIPLE_RECNO_WRITE_INIT</a> 
                and <a class="xref" href="DB_MULTIPLE_RECNO_WRITE_NEXT.html" title="DB_MULTIPLE_RECNO_WRITE_NEXT">DB_MULTIPLE_RECNO_WRITE_NEXT</a>.
            </p>
                <p>
                See the <a class="xref" href="dbt.html#dbtlist" title="DBT and Bulk Operations">DBT and Bulk Operations</a> for more information on
                working with bulk updates.
            </p>
                <p>
                The <code class="literal">DB_MULTIPLE_KEY</code> flag may only be used alone.
            </p>
              </li>
            </ul>
          </div>
        </div>
      </div>
      <div class="sect2" lang="en" xml:lang="en">
        <div class="titlepage">
          <div>
            <div>
              <h3 class="title"><a id="idp49444120"></a>Errors</h3>
            </div>
          </div>
        </div>
        <p>
            The <code class="methodname">DB-&gt;del()</code> <span>
            <span>
                 method may fail and return one of the following non-zero errors:
            </span>
            
        </span>
        </p>
        <div class="sect3" lang="en" xml:lang="en">
          <div class="titlepage">
            <div>
              <div>
                <h4 class="title"><a id="idp49454272"></a>DB_FOREIGN_CONFLICT</h4>
              </div>
            </div>
          </div>
          <p>
                A <a class="link" href="dbassociate_foreign.html" title="DB-&gt;associate_foreign()">foreign key constraint violation</a> 
                has occurred. This can be caused by one of two things:
            </p>
          <div class="orderedlist">
            <ol type="1">
              <li>
                <p>
                            An attempt was made to add a record to a
                            constrained database, and the key used for that
                            record does not exist in the foreign key
                            database.
                        </p>
              </li>
              <li>
                <p>
                            <a class="link" href="dbassociate_foreign.html#associate_foreign_DB_FOREIGN_ABORT">DB_FOREIGN_ABORT</a> 
                            was declared for a foreign key database, and then
                            subsequently a record was deleted from the
                            foreign key database without first removing it
                            from the constrained secondary database.
                        </p>
              </li>
            </ol>
          </div>
        </div>
        <div class="sect3" lang="en" xml:lang="en">
          <div class="titlepage">
            <div>
              <div>
                <h4 class="title"><a id="idp49446232"></a>DB_LOCK_DEADLOCK</h4>
              </div>
            </div>
          </div>
          <p>
                A transactional database environment operation was selected to resolve
                a deadlock.
            </p>
        </div>
        <div class="sect3" lang="en" xml:lang="en">
          <div class="titlepage">
            <div>
              <div>
                <h4 class="title"><a id="idp49467624"></a>DB_LOCK_NOTGRANTED</h4>
              </div>
            </div>
          </div>
          <p>
                A Berkeley DB Concurrent Data Store database environment configured
                for lock timeouts was unable to grant a lock in the allowed time.
            </p>
          <p>
                You attempted to open a database handle that is configured
                for no waiting exclusive locking, but the exclusive lock could not be
                immediately obtained. See
                <a class="xref" href="dbset_lk_exclusive.html" title="DB-&gt;set_lk_exclusive()">DB-&gt;set_lk_exclusive()</a>
                for more information.
            </p>
        </div>
        <div class="sect3" lang="en" xml:lang="en">
          <div class="titlepage">
            <div>
              <div>
                <h4 class="title"><a id="idp49478736"></a>  DB_REP_HANDLE_DEAD</h4>
              </div>
            </div>
          </div>
          <p>
                When a client synchronizes with the master, it is possible for committed
                transactions to be rolled back. This invalidates all  the database and cursor
                handles opened in the replication environment. Once this occurs, an attempt to use
                such a handle will 
                
                return <code class="literal">DB_REP_HANDLE_DEAD</code>.
                The application will need to discard the handle and open a new one in order to
                continue processing.
            </p>
        </div>
        <div class="sect3" lang="en" xml:lang="en">
          <div class="titlepage">
            <div>
              <div>
                <h4 class="title"><a id="idp49422080"></a>DB_REP_LOCKOUT</h4>
              </div>
            </div>
          </div>
          <p>
                The operation was blocked by client/master synchronization.
            </p>
        </div>
        <div class="sect3" lang="en" xml:lang="en">
          <div class="titlepage">
            <div>
              <div>
                <h4 class="title"><a id="idp49447088"></a>DB_SECONDARY_BAD</h4>
              </div>
            </div>
          </div>
          <p>
                A secondary index references a nonexistent primary key.
            </p>
        </div>
        <div class="sect3" lang="en" xml:lang="en">
          <div class="titlepage">
            <div>
              <div>
                <h4 class="title"><a id="idp49498176"></a>EACCES</h4>
              </div>
            </div>
          </div>
          <p>
                An attempt was made to modify a read-only database.
            </p>
        </div>
        <div class="sect3" lang="en" xml:lang="en">
          <div class="titlepage">
            <div>
              <div>
                <h4 class="title"><a id="idp49498584"></a>EINVAL</h4>
              </div>
            </div>
          </div>
          <p>
                An invalid flag value or parameter was specified.
            </p>
        </div>
      </div>
      <div class="sect2" lang="en" xml:lang="en">
        <div class="titlepage">
          <div>
            <div>
              <h3 class="title"><a id="idp49473040"></a>Class</h3>
            </div>
          </div>
        </div>
        <p>
            <a class="link" href="db.html" title="Chapter 2.  The DB Handle">DB</a>  
        </p>
      </div>
      <div class="sect2" lang="en" xml:lang="en">
        <div class="titlepage">
          <div>
            <div>
              <h3 class="title"><a id="idp49468960"></a>See Also</h3>
            </div>
          </div>
        </div>
        <p>
            <a class="xref" href="db.html#dblist" title="Database and Related Methods">Database and Related Methods</a> 
        </p>
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